Hi Guys, I know this will sound like a proper newbie question (as i am one!) but i am getting confused about the file size of HD blu ray rips and the claims of their quality. I am looking to back up my blu ray disks by ripping them to PC but i have seen people claiming to have 4.5gb files as 720p hd quality. That sounds odd to me as a DVD rip would be around that size. Also, i have seen 6gb, 8gb & 11gb rip files claiming to be 1080p quality (whereas another person told me you can't have proper 1080p rip unless it is around 35gb in size!). Can anyone give me a rough guide to what size a good 720p and 1080p rip should be? A rough estimate would do. Regards, Shuja
It seems like the terms may be confusing you. Generally, when you rip a Blu Ray, you end up with an exact copy of the video in its full size (20, 30, 35GB....etc.) without the menus or extras. The smaller size videos are the result of encoding - compressing the video using H264 compression to maintain a high quality at lower bitrates resulting in a smaller file size. Quality depends on how good you personally want your video to look and that depends on how much you care. You won't know that until you try a few and compare. There are lots of 4.5GB 720p movies because they are small enough to fit on a single layer DVD-R, and the increased quality doesn't justify the cost to a lot of people. Same goes for the 8GB 1080p encodes that are floating around - they fit on a DVD-R double layer disc. The end result serves the needs of most in terms of the cost of the backup and saving hard drive space. In most cases, these encodes look great. So, yes you can end up with a great looking 8GB 1080p movie that is "1080p HDTV worthy." You can also have a 4.5GB 720p movie that looks great when upscaled on a 1080p HDTV. H264 compression can result in an encode transparent to the source. In other words, you can't tell the difference. But....most people are satisfied with close to transparency. In some cases it's difficult to tell the difference, and in other cases it's quite obvious. Some people choose a default setting when they encode, in order to bang out movies that will always be the same size (ie. 4.5GB or 8GB). The result depends on the movie. There are a lot of settings that can be tweaked to get different results. I usually encode stuff like comedies to 720p at a very good quality setting and get a movie around 6-7GB (from a 20GB source file). I'll encode movies that I really enjoy to 1080p at an excellent quality setting and get a movie at around 10-12GB (from a 30GB source). I'll encode my favorite movies that I think are great to 1080p at an insane quality setting and get a movie at around 15-17GB (from a 30GB source). Again, quality is subjective. I encoded Paper Heart to 1080p at a lower quality preset and ended up with a 4GB movie. I think the source was 20GB. I could barely tell the difference when comparing frame by frame. Other movies I've tried this with looked like crap. Everyone has their own gauge and their own way of encoding. If you have the time, experiment. If not, there are quick and dirty ways to do it. Buy a couple of Blu Rays, and then do some encodes of your own (or download some) and compare the image quality for yourself. You may see very little difference, despite the file size of the encode. Hope that helped a little. Check out the BD Backup sticky for a comprehensive list of tools to use for encoding and also for more in depth explanations.
